AA/US: PHX/CLT/PHL/RDU - LHR $750 June/July
AA/US have a ~750 a.i. r/t fare for June 13 - July 13 departures from PHX/CLT/PHL/RDU to LHR. The fare is valid for all days of the week and has a Sunday night minimum stay and three day advance purchase requirement. The maximum stay is 6 months. I checked a few other hubs (DCA, MIA, ORD, NYC, LAX, STL) and the fare was not available from those.
Not mileage run material but certainly a good deal for some options and markets such as the RDU-LHR non-stop, especially for summer travel.
Example:
July 4 PHX-CLT-LHR, July 5 LHR-CLT-PHX $748 on usairways.com, 11,531 miles, 6.8 cpm